jshintignore: Add jquery.fullscreen.js

Follows-up 37835854c7. Though it passes out jshint config, it
won't pass jscs and even if it would, it's upstream so it doesn't
have to pass.

Change-Id: Ia67da79b74252065c348a932e700926700030722
Merge "jshintignore: Add jquery.fullscreen.js"